[llvm] [Instrumentation] Fix EdgeCounts vector size in SetBranchWeights (PR #99064)

[Mircea Trofin via llvm-commits]

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@@ -1623,10 +1623,12 @@ void PGOUseFunc::setBranchWeights() {
       continue;
 
     // We have a non-zero Branch BB.
-    unsigned Size = BBCountInfo.OutEdges.size();
-    SmallVector<uint64_t, 2> EdgeCounts(Size, 0);
+    unsigned OutEdgesCount = BBCountInfo.OutEdges.size();
+    unsigned SuccessorCount = BB.getTerminator()->getNumSuccessors();
+
+    SmallVector<uint64_t, 2> EdgeCounts(SuccessorCount, 0);
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mtrofin wrote:

Can you add a comment as to why we need to dimension EdgeCounts like that? (basically "`Removed` edges don't appear in `OutEdges`). Also I'd add an `assert(OutEdgesCount <= SuccessorCount)

otherwise LGTM, but wait also for @ellishg and/or @xur-llvm 

https://github.com/llvm/llvm-project/pull/99064